Drainage control system



1953 L. J. MARTINIAK ETAL ,6

DRAINAGE CONTROL SYSTEM Filed Nov. 28, 1952 Patented Dec. 15, 1953DRAINAGE CONTROL SYSTEM Leonard .1. Martinialr, Chicago, and John W.Duscnberry, Melrose Park, Ill., assignors to General Electric Company, acorporation of New York Application November 28, 1952, Serial No.323,032

10 Claims.

This invention relates to improvements in drainage control systems fordishwashing machines in which an impeller or screw is driven atrelatively high speed to cause washing and rinsing liquid to be broughtforcefully into contact with. the articles contained in a dishwashertub.

In dishwashing machines of the domestic type particularly, it is apractical necessity to conserve water. As a result each washing orrinsing operation uses, in a presently well-known domestic dishwasher,only about twelve pints of water which is recirculated many times overthe articles to be washed and rinsed. Drainage loss must be preventedduring the washing or rinsing operations and yet the drainage systemmust provide for quickly removing the liquid at the end of theoperation. Drain valves as presently known and used require electricallyor mechanically timed devices to operate them between open and closedpositions and are subject not only to failures of such timing devicesbut to sticking or other faulty operation due to the lodgement of foodparticles.

It is an object of our invention to provide a valve mechanism directlyassociated with the impeller so as to be open when the impeller isquiet, but automatically assuming a closed position in response tocentrifugal forces generated by impeller rotation.

It is another object of the invention to provide a valve member having aplurality of individually relatively small drainage ports, therebyreducing leakage if one of the valve elements is held partially openduring a non-drainage period.

It is another object of the invention to provide a valve mechanism fixedto the impeller to rotate therewith and effective solely by reason ofits rtation to prevent the flow of liquid to a drainage opening disposedabout the axis of rotation of the impeller.

It is a still further object or" the invention to provide a valvemechanism which may easily be repaired or replaced in the field withoutrequiring other than a removal of the impeller.

In a presently preferred embodiment of our invention, these and otherobjects and advantages are accomplished by providing a cylindrical valvebody member with a plurality of drain ports extending upwardly from oneedge thereof and providing on the interior of said valve body an equalnumber of resilient flaps normally biased away from said ports butoperable under centrifugal forces engendered by rotation of said body tomove into port-closing position. The said body is then suitably mountedwithin the hub of the impeller, with the bottom edge of the body closelyadjacent the dishwasher tub bottom. The drainage opening of the tub isdisposed concentrically about the impeller shaft. When the impeller isquiet following a washing or rinsing operation, the resilient flapswithdraw from the ports, thus permitting liquid in the tub to reach thedrainage opening. On the other hand, when the valve is rotating with theimpeller, the valve flaps swing into closing position, thus preventingthe water content of the tub from reaching the .rainage opening. We havefound that by making the valve body of a material having a wallthickness of the order of of an inch, edge walls of the valve portscreate a turbulence within the body of the liquid when the impeller isrotating rapidly. This turbulence is remarkably effective to preventwater from reaching the interior of the valve and therefore supplementsthe valve elements in preventing unwanted drainage.

Other features and advantages of the invention will be apparent from thefollowing detailed description of embodiments thereof read in connectionwith the accompanying drawing in which:

Fig. 1 is a fragmentary sectional elevation of the bottom of adishwasher tub showing an application of one embodiment of ourinvention. The impeller is quiet, permitting any water content to drainas indicated by the arrows;

Fig. 2 is a section through the valve portion along the lines 2-2 ofFig. 1 showing the several valve elements in drainage position;

Fig. 3 is a view similar to Fig. 2 with the valve ports closed duringrotation of the impeller; and

Figs. 4 and 5 are respectively a vertical section and a plan sectionshowing a second form of valve construction.

In Fig. 1 there is fragmentarily shown the lower tub portion of adishwasher of the type, for example, fully described in Koertge U. S.Patent 2,422,022 granted June 10, 1947, for Dishwashing and DryingApparatus. In dishwashers of this type, a tub I is suitably supportedwithin an outside casing (not shown). The tub has an open front and thecasing pivotally supports a door movable between a substantiallyvertical closed position and a substantially horizontally open position.Within the tub are dish racks (not shown) arranged to be drawn outwardlythrough the open front of the tub loaded with dishes and returned to thetub; whereupon detergent may be added, the door closed and thedishwasher operated.

By various means new well-known in the art, the dishwasher proceedsthrough a program involving timed operations in which the dishes arerinsed, washed, given one or more rinses following washing, and then areair-dried. Each of the rinsing and washing operations requires theintroduction into the tub of about twelve pints of water, and after eachsuch operation the water is caused to drain from the tub. With specificreference to the instant disclosure, the wash and rinse liquid iscirculated and recirculated over the articles within the tub by amotor-driven impeller or screw 2, removably fixed to the vertical shaftextension 3 of the motor l, attached by any suitable brackets 5 to thebottom of the tub or alternatively to a drainage fitting i3 suitablysecured to said tub in watertight relation therewith. As shown, saiddrainage fitting may comprise a casting having an annular watercollector channel I, sloping toward a discharge tube 8 to which may beaiiixed in any suitable manner a pipe 9 communicating with a drain trap(not shown) in the plumbing system of the building. Rising from thecentral portion of the drainage fitting is a tubular guard it whichextends upwardly about shaft 3 to a level which prevents liquid in thetub from spilling into the open end of said tube and flowing into themotor space. Removably disposed about said impeller is a screen i i; andfixed within the tub and surrounding the impeller, so as to be in thepath of air circulation during the final dish drying stage of operation,is a metallic sheathed heating element 1?! as specifically disclosed insaid Koertge patent.

The bottom of the tub I slopes to form a sump, at the center of which isan opening Hi compri ing the only drainage opening from the dishwashertub. The present invention provides a simple and effective control overthe drainage of spent wa hing and rinsing liquid.

It will be understood that shaft 3 rotates at high speed: in the usualdomestic dishwasher, a 1750 R. P. M. motor is used. It is assumed thatthe shaft will rotate in a counter-clockwise direction.

In the embodiment Figs. 1, 2 and 3, the valve device includes acylindrical body is sized to fit snugly within the cylindrical hub ofthe impeller 2 in surface contact with the inner wall thereof. Atintervals about the lower portion of said body, we provide a pluralityof valve ports H5 which are advantageously of rectangular cross section.Preferably the valve ports comprise rectangular notches open at thebottom and extending upward a proximately to the plane of the bottom ofthe impeller hub. When the valve body is in proper operative position,the bottom wall of the tub becomes in effect the fourth wall of thevalve port opening, although it should be noted that it is not necessaryfor the bottom ed e of the valve body to be in actual surface contactwith the tub. Cooperating with each valve port is a flapper valve memberll secured at one end to the valve body and arranged to move between anormally retracted or open position shown in 2 and the closed positionof Fig. 3, in which the flapper valve effectively closes the valve portagainst escape of liquid. It is apparent from Fig. 3 that the flappervalve is sufficiently longer than the port It to insure a substantialoverlap at the end of the valve port, and in this way prevent theflapper valve from driving through the valve port as it swings closed bycentrifugal force as later explained.

The flapper valves are of resilient material biased to assume a normallyopen position. Various constructions are possible: body it may, forexample, be of rigid plastic and the flapper valves of a resilient orspringable material suitably afilxed thereto. We consider, however, thatit is best to mold the body and flapper valves of an elastomericmaterial such as natural rubber compounds or plastics such as thatmarketed under the name neoprene in which event the flapper valves areintegral with the valve body. A medium-stiff rubber in the 60-70clurometer range appears to be well suited to the purpose.

In the embodiment of Figs. 4 and 5, the valve body 15.! is similarlyformed with valve ports l6.l. The flapper valves I'M are arranged topivot in a vertical rather than a horizontal plane. The fiappers arebiased into the normally open position of Fig. 4.- and to limit theextent of movement in valve closing direction, we propose to bevel theside Walls of the valve ports so that their maximum width is radiallyinnermost. By matchingly bevelling the side walls of the flapper valves,the valves will seat snugly into the valve ports without substantialdanger of driving through the ports.

It will thus be seen that we have provided a drainage control system inwhich it is necessary only to interrupt the operation of the impellerwhenever washing or rinsing liquid is to flow to the drain. During apreliminary rinse period, for example, when gross soil is to be removedfrom the dishes before an actual washing operation takes place, rinsewater is introduced into the dishwasher tub while the impeller issilent, whereupon the water will flow over the dishes and articles andthen pass through the open valve ports into the drainage system. Thenext operation would be to wash the articles and therefore before thewater is caused to flow into the tub the timing apparatus (not shown)starts the motor so that the impeller will be approachina its operationspeed before the water enters. As the impeller gains speed, centrifugalforces acting on the flapper valves 5! or NJ throw them outwardly intoclosing position. Then at the end of or slightly before the terminationof the washing operation, the motor circuit is opened so that theimpeller will cease rotating. The valve elements return to theirnormally open position, permitting full drainage. Using a plurality ofrelatively small valve ports and fiappers makes an individual port lesscritical. That to say, a valve flapper might be held partially open by aforeign body without causing excessive water loss. Conversely, adequatedrainage is provided for even if one of the flapper valves should stickin closed position.

By sizing the valve cylinders l5 and I5.| for frictional engagement withthe inside of the impeller hub, it is not necessary mechanically tofasten the valve cylinder to the impeller to insure rotation therewith.This simplifies installation and. removal. For example, to remove thevalve body for inspection or repair, it is necessary only to remove theimpeller from its shaft and then to remove and replace the cylindricalvalve body as necessary. The impeller is readily accessible through theopen door of the dishwasher tub. This facility of inspection and removalmakes it entirely unnecessary to dismantle the dishwasher apparatus asis now required to service most of the conventional domesticdishwashers.

We have discovered that in the Fig. 3 form particularly, the squarevertical wall of each valve port 16 causes a. turbulence in the sumpimmediately around the valve body which appears to throw the liquid awayfrom the valve member This action is particularly effective when thevalve body is of the order of one-eighth inch in thickness. Thisturbulence-creating action in a sense assists the valve flapper membersin preventing loss or" liquid.

While we have shown particular embodiments of our invention, it will beunderstood, of course, that we do not wish to be limited thereto sincemany modifications may be made; and we there fore contemplate by theappended claims to cover any such modifications as fall within the truespirit and scope of our invention.

We claim:

1. In a dishwashing machine of the type having a tub for containingarticles to be washed in a quantity or" liquid and a motor drivenimpeller disposed adjacent a wall of said tub for rotation about a fixedaxis to distribute said liquid throughout said tub; the improvement inmeans for controlling drainage from said tub, comprising a drainageopening in said tub Wall about impeller axis, a cylindrical valve bodyassociated with said impel er for rotation therewith, said valve bodyextending from said impeller to encircle said drainage opening in closeproximity to said tub wall, said valve body having about itscircumference a plurality of openings disposed immediately adjacent saidtub wall, and a flapper valve pivotally carried said valve bodyinteriorly thereof for cooperation with each said valve body opening,the respective flapper valves being biased away from their associatedvalve openings to permit flow therethrough when said impeller is at restbut responsive to centrifugal forces engendered by rotation of saidimpeller to move against valve body to close said openings.

2. In a dishwashing machine of the type having a tub for containingarticles to be washed in a quantity of liquid and a motor drivenimpeller disposed adjacent a wall of said tub for rotation about a fixedaxis to distribute said liquid throughout said tub; the improvement inmeans for controlling drainage from said tub, comprising a drainageopening in said tub wall about said impeller axis, a cylindrical valvebody carried by said impeller for rotation therewith, said valve bodyextending from said impeller to encircle said drainage opening in closeproximity to said tub wall, said valve body having about itscircumference a plurality of openings disposed immediately adjacent saidtub wall, and valve means pivotally carried by said valve bodyinteriorly thereof for cooperation with each said valve body opening,said valve means being biased inwardly away from their associated valveopenings to permit flow therethrough when said impeller is at rest butresponsive to centrifugal forces engendered by rotation of said impellerto move outwardly against said valve body to close said openings.

3. In a dishwashing machine of the type hav ing a tub for containingarticles to be washed in a quantity of liquid and a motor drivenimpeller disposed adjacent a wall of said tub for rotation about a fixedaxis to distribute said liquid throughout said tub; the improvement inmeans for controlling drainage from said tub, comprising a drainageopening in said tub wall about said impeller axis, a cylindrical,water-impervious valve body associated with said impeller for rotationtherewith, said valve body extending coaxially from said impeller toencircle said drainage opening in close proximity to said tub wall, saidvalve body having formed in its wall equidistantly about itscircumference a plurality of open-ended passages in which the open endsface said tub wall, and a flapper valve by said valve body forcooperation with each said valve body opening, the respective flappervalves boing pivotally affixed to said valve body at the leading edge ofeach said passage as respects the direction of rotation of said valvebody and ex tending interiorly of said body into overlapping relationwith said body wall beyond the trailing edge of said passage, saidflapper valves being biased away from their associated body wallpassages to permit flow therethrough when said impeller is at rest butresponsive to centrifugal forces engendered by rotation of said impellerto move against said valve body to close said openings and therebyprevent flow of liquid to said drainage opening.

4. Drainage control means as in claim 3, in which said flapper valvesare integral with said valve body,

5. Drainage control means as in claim 3, in which said flapper valvesand said valve body are integral and of a semi-stiff elastomericmaterial having the resiliency characteristic of rubber of 60-70durometer.

6. Drainage control means as in claim 3, in which said flapper valvespivot about an axis parallel to the axis of rotation of said impeller.

7. In a dishwashing machine of the type having a tub for containingarticles to be washed in a quantity of liquid and a motor drivenimpeller disposed adjacent a bottom wall of said tub for rotation abouta fixed vertical axis to distribute said liquid throughout said tub; theimprovement in means for controlling drainage from said tub, comprisinga drainage opening in said bottom wall radially outward of said impelleraxis, a cylindrical valve body frictionally secured to said impeller forrotation therewith, said valve body extending coaxially from saidimpeller to encircle said drainage opening in close proximity to saidtub wall, said valve body having about its circuinference a plurality ofopenings disposed immediately adjacent said tub wall, and a flappervalve carried by said valve body for pivotal movement about a verticalaxis for cooperation with each said valve body opening, each saidflapper valve axis being in the leading portion of said opening asrespects the direction of rotation of said impeller, the respectiveflapper valves extending inwardly of said valve body into overlappingrelation with the wall thereof rearwardly of the trailing edge of theassociated valve openings and being biased with respect thereto topermit flow therethrough when said impeller is at rest but responsive tocentrifugal forces engendered by rotation of said impeller to moveagainst said valve body to close said openings.

8. Drainage control means as in claim 7, in which the trailing edge ofeach said valve opening cooperates with its associated flapper valvewhen the latter is in closing position to define a substantiallytriangular pocket effective to create turbulence in a body of liquidabout said valve body and to repel such liquid from said valve body.

9. In a dishwashing machine of the type having a tub for containinarticles to be washed in a quantity of liquid and a motor drivenimpeller at the bottom of said tub for rotation about a fixed axis todistribute said liquid throughout said tub; the improvement in means forcontrolling 7 drainage from said tub, comprising a drainage opening insaid tub wall about said impeller axis, a cylindrical valve body ofsemi-stiff rubberlike material secured to said impeller for rotationtherewith, said valve body extending ooaxially from said impeller toencircle said drainage opening in close proximity to said tub wall, saidvalve body formed about its circumference with a plurality of relativelysmall, equiangularly spaced openings, and a flapper valve horizontallypivoted about each said opening and extending downwardly into operativerelation therewith, said flapper valves being normally biased to moveradially inward of said valve body to uncover said openings for liquidflow therethrough when the impeller is at rest but moving in response tocentrifugal forces engendered by rotation of said impeller to close saidopenings.

10. Drainage control means as in claim 9, in which the side edges ofsaid valve body openings are beveled to enlarge said openings in aradially inward direction and the side edges of said flapper valves arematchingly beveled.

LEONARD J. MARTINIAK. JOHN W. DUSENBERRY.

No references cited.

